KR20130055288A - Voice coil motor and driving method thereof - Google Patents

Abstract

PURPOSE: A voice coil motor and a driving method thereof are provided to reduce power consumption by driving with a low current and control a focus between a lens and an image sensor within a fast time. CONSTITUTION: A voice coil motor(600) includes a stator(100), an actuator(200), a base(300), and a lower elastic member(400). The stator includes a coil block or a housing which fixes the coil block. The actuator is arranged inside of the coil block and includes a bobbin to which a lens is fixed or a magnet which faces with the coil block in the bobbin. The base fixes the housing, forms an opening in a position which corresponds to the lens, and forms a bobbin holding groove which accommodates the lower side of the bobbin on the upper side which faces with the bobbin. The lower elastic member forms a gap between the lower side of the bobbin and the bottom which is formed by the bobbin holding groove regardless of a posture of an operator when a drive signal is not applied to the coil block.

Description

VOICE COIL MOTOR AND DRIVING METHOD THEREOF

The present invention relates to a voice coil motor driven in both directions from a reference position and operated with low current and low power consumption, and a driving method thereof.

Recently, mobile phones and the like with built-in miniature digital cameras have been developed.

In the case of a conventional digital camera applied to a mobile phone, the distance between an image sensor and a lens for changing external light into a digital image or a digital image cannot be adjusted, but a voice coil motor for controlling the distance between the image sensor and the lens has recently been used. The same lens driving device has been developed to enable improved digital images or digital images in ultra-compact digital cameras.

In general, a voice coil motor has a lens mounted therein, and a bobbin disposed at the base moves upward from the base to adjust a gap between the lens and an image sensor disposed at the rear of the base.

In addition, the bobbin of the voice coil motor is coupled to the leaf spring so that the bobbin is always in contact with the base by the elastic force of the leaf spring when the voice coil motor is not operated. That is, the bobbin of the conventional voice coil motor is driven in one direction toward the top with respect to the base.

 In order to drive the voice coil motor by driving the voice coil motor only in one direction, a driving force larger than the self-weight of the bobbin and the elastic force of the leaf spring is required, and thus, the power consumption of the voice coil motor is greatly increased.

In addition, in order to drive the voice coil motor requires a driving force greater than the self-weight of the bobbin and the elastic force of the leaf spring has a problem that the size of the coil wound on the magnet or bobbin is increased to increase the overall size of the voice coil motor.

In addition, when the shape of the leaf spring is deformed, the focus between the lens and the image sensor is not made accurately has a problem that the image quality is significantly lowered.

The present invention provides a voice coil motor and its driving method suitable for driving the mover with a smaller current.

The technical object of the present invention is not limited to the above-mentioned technical objects and other technical objects which are not mentioned can be clearly understood by those skilled in the art from the following description will be.

In one embodiment, the voice coil motor includes a stator including a coil block and a housing for fixing the coil block; A mover including a bobbin disposed inside the coil block and having a lens fixed therein, and a magnet disposed on the bobbin facing the coil block; A base in which the housing is fixed and an opening is formed at a position corresponding to the lens, and a bobbin receiving groove is formed on an upper surface facing the bobbin to receive a lower surface of the bobbin; And a lower elasticity fixed to the bobbin and the base such that a gap is formed between the bottom surface of the bobbin and the bottom surface formed by the bobbin receiving groove regardless of the posture of the mover when no driving signal is applied to the coil block. Member.

In one embodiment, the voice coil motor includes a stator including a coil block and a housing for fixing the coil block; A mover including a bobbin disposed inside the coil block and having a lens fixed therein, and a magnet disposed on the bobbin facing the coil block; A base in which the housing is fixed and an opening is formed at a position corresponding to the lens, and a bobbin receiving groove is formed on an upper surface facing the bobbin to receive a lower surface of the bobbin; And a lower elastic member fixed to the bobbin and the base such that a gap is formed between a bottom surface of the bobbin and a bottom surface formed by the bobbin receiving groove, wherein the bobbin supported by the lower elastic member includes the coil block. And a first direction away from the base by a first force generated by the magnet, and a second direction closer to the base by the bobbin receiving groove.

In one embodiment, the driving method of the voice coil motor is a base having a bobbin receiving groove, disposed on the base and disposed on the bobbin receiving groove and including a magnet, fixed to the base and facing the magnet. A voice coil motor including a stator including a coil block and an elastic member for floating the mover on an upper portion of the bobbin receiving groove, wherein the bobbin is moved to a reference position by applying an initial driving signal to the coil block. Aligning; Moving the bobbin from the reference position to a focus position by applying a driving current of increasing or decreasing level to the coil block; And stopping the bobbin at a position corresponding to the optimum focus by maintaining the level of the drive current constant when an optimum focus is formed between the lens and the image sensor module.

In one embodiment, the driving method of the voice coil motor is a base having a bobbin receiving groove, disposed on the base and disposed on the bobbin receiving groove and including a magnet, fixed to the base and facing the magnet. And a stator including a coil block and an elastic member for floating the mover on the bobbin receiving groove, wherein the bobbin is moved to a reference position by applying a reference current to the coil block to align the bobbin; Moving the bobbin from the reference position to a focus position by applying a driving current of increasing or decreasing level to the coil block; And stopping the bobbin at a position corresponding to the optimum focus by maintaining the level of the drive current constant when an optimal focus is formed between the lens and the image sensor module.

According to the voice coil motor and a driving method thereof according to the present invention, a bobbin mounted with a lens is floated from a bobbin accommodation groove formed on an upper surface of a base on which an image sensor is mounted, and a bobbin is applied by applying a forward current or a reverse current to the coil block. By driving the containing mover in both directions away from the base or approaching the base, the voice coil motor can be driven with low current, reducing power consumption and adjusting the focus between the lens and image sensor in a shorter time. It has an effect of reducing contact noise due to driving.

1 is an exploded perspective view of a voice coil motor according to an embodiment of the present invention.
Fig. 2 is an assembled sectional view of Fig. 1. Fig.
3 is a cross-sectional view conceptually illustrating the voice coil motor illustrated in FIG. 1.
4 is a graph showing a relationship between a driving current amount and a moving amount for driving the voice coil motor shown in FIG. 3.
FIG. 5 is a block diagram illustrating a driving circuit for raising or lowering the mover of the voice coil motor of FIG. 1.
6 and 7 are block diagrams illustrating that a forward current or a reverse current is applied to the coil block by the driving circuit of FIG. 5.
8 and 9 are graphs for describing a method of driving the voice coil motor illustrated in FIG. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The sizes and shapes of the components shown in the drawings may be exaggerated for clarity and convenience. In addition, terms defined in consideration of the configuration and operation of the present invention may be changed according to the intention or custom of the user, the operator. The definitions of these terms should be interpreted based on the contents of the present specification and meanings and concepts in accordance with the technical idea of the present invention.

1 is an exploded perspective view of a voice coil motor according to an embodiment of the present invention. Fig. 2 is an assembled sectional view of Fig. 1. Fig.

1 and 2, the voice coil motor 600 includes a stator 100, a mover 200, a base 300, and a lower elastic member 400. In addition, the voice coil motor 600 may include a cover can 500.

The stator 100 includes a coil block 120 and a housing 150. The stator 100 generates a magnetic field for driving the mover 200 to be described later.

The coil block 120 is formed by winding, for example, a long wire insulated by an insulating resin in a tubular shape. When a voltage having a voltage difference is applied to the coil block 120 formed by winding a long wire insulated by an insulating resin, a magnetic field is generated from the coil block 120, and the direction of the magnetic field flows in the coil block 120. It changes according to the direction of the current.

The housing 150 fixes the coil block 120. The housing 150 includes, for example, the housing body 152 and the pillars 154.

The housing body 152 is formed, for example, in a rectangular plate shape, and an opening 153 is formed in the central portion of the housing body 152 to expose a lens mounted on a bobbin to be described later.

The upper surface of the housing body 152 is formed with a plurality of coupling bosses 156 for fixing the upper elastic member to be described later.

The pillars 154 protrude from the four corners of the lower surface of the housing body 152 facing the base 300, respectively. The inner surface of the coil block 120 is fixed to the outer circumferential surface of the pillars 154. Pillars 154 may be coupled to the upper surface of the base 300 to be described later.

In one embodiment of the present invention, the coil block 120 is attached to the pillars 154 of the housing 150 by an adhesive or the like or wound directly on the pillars 154 of the housing 150 while being wound in a cylindrical shape. Can be.

The mover 200 includes a bobbin 210 and a magnet 250.

A cylindrical lens 205 is fixed inside the bobbin 210. The mover 200 moves with respect to the stator 100 to adjust the distance between the image sensor and the lens 205 disposed on the lower surface of the base 300 to be described later.

The bobbin 210 is, for example, formed in a cylindrical shape with a hollow, and a thread for fixing the lens 205 is formed on the inner circumferential surface of the bobbin 210.

Flat magnet fixing portions 215 are formed on the outer circumferential surface of the bobbin 210 to fix the plurality of magnets 250. For example, four magnet fixing parts 215 are formed at equal intervals on the outer circumferential surface of the bobbin 210, for example.

The magnets 250 are formed, for example, in a plate shape, and the magnets 250 are fixed to the respective magnet fixing parts 215 formed on the outer circumferential surface of the bobbin 210. Each magnet 250 may be attached to the magnet fixing part 215 by an adhesive or the like.

Each magnet 250 is disposed to face the coil block 120 of the stator 100.

The base 300 is, for example, formed in a rectangular plate shape and serves to fix the stator 100.

The base 300 is, for example, formed in a rectangular plate shape and serves to fix the stator 100.

In the central portion of the base 300 is formed an opening 310 through which light passing through the lens 205 embedded in the bobbin 210 of the mover 200 passes.

Four pillars 325 are formed at four corners of the upper surface 320 of the base 300 formed in a plate shape, and the coupling pillar 325 mutually couples the cover can 500 and the base 300 to be described later. It plays a role.

An IR filter 301 and an image sensor (not shown) for generating an image corresponding to light passing through the lens 205 of the bobbin 210 are fixed to the rear surface of the base 300.

On the other hand, the upper surface 320 of the base 300 is formed with a bobbin receiving groove 330 formed concave from the upper surface 320. The bobbin receiving groove 330 serves to receive the lower end of the bobbin 210.

The bobbin receiving groove 330 may be formed larger than the plane of the bobbin 210, and a part of the bobbin 210 and the base 300 may overlap each other by the bobbin receiving groove 330.

In one embodiment of the present invention, the depth of the bobbin receiving groove 330 is formed in consideration of the stroke length of the mover 200.

Meanwhile, the shock absorbing member 350 formed along the opening 310 of the base 300 is disposed on the bottom surface 335 of the bobbin 210 formed by the bobbin accommodation groove 330. For example, the shock absorbing member 350 absorbs the impact due to the collision between the bobbin 210 and the bottom surface 335 of the base 300.

In one embodiment of the present invention, the shock absorbing member 350 may include any one of a sponge, a synthetic resin having elasticity and rubber, and the shock absorbing member 350 may be formed in an annular plate shape having a thin thickness. Can be.

The lower elastic member 400 elastically supports the bobbin 210 of the mover 200, and the lower elastic member 400 has a lower surface of the bobbin 210 of the mover 200 to receive the bobbin of the base 300. Float on the upper portion of the groove 330.

That is, the lower elastic member 400 is a bobbin formed on the lower surface of the bobbin 210 and the upper surface 320 of the base 300 regardless of the posture of the bobbin 210 when no current is applied to the coil block 120. A gap is formed between the bottom surface 335 formed by the accommodation groove 330.

Here, the posture of the bobbin 210 means that the lens of the bobbin 210 faces downward, the lens of the bobbin 210 faces upward, or the lens of the bobbin 210 is disposed parallel to the ground.

The lower elastic member 400 includes an inner lower elastic portion 410, an outer lower elastic portion 420, and a connection lower elastic portion 430.

The inner lower elastic part 410 is formed, for example, in an annular ring shape, and the inner lower elastic part 410 is coupled to the lower surface of the bobbin 210. The inner lower elastic part 410 is coupled to the lower surface of the bobbin 210 by, for example, an adhesive or heat welding.

Since the inner lower elastic part 410 is coupled to the lower surface of the bobbin 210, the inner lower elastic part 410 is also formed to have a size that is inserted into the bobbin receiving groove 330 of the base 300.

The outer lower elastic part 420 is disposed outside the inner lower elastic part 410, and the outer lower elastic part 420 is formed in a rectangular frame shape.

The outer lower elastic part 420 is formed to have a larger size than the bobbin receiving groove 330 of the base 300, and thus the outer lower elastic part 420 is disposed on the upper surface 320 of the base 300. The outer lower elastic portion 420 may be fixed on the upper surface 320 of the base 300 by, for example, the pillars 154 of the housing 150 of the stator 100.

The connection lower elastic part 430 elastically connects the inner lower elastic part 410 and the outer lower elastic part 420 to each other, and the inner lower elastic part 410 has elasticity by the connecting lower elastic part 430. do.

In one embodiment of the present invention, the bobbin 210 is floated on the bobbin receiving groove 330 of the base 300 by the lower elastic member 300.

The inner lower elastic part 410 is spaced apart from the bottom surface 335 formed by the bobbin receiving groove 330, and when the driving signal is not applied to the coil block 120, the inner lower elastic part 410 and the outer side thereof. The lower elastic part 420 and the connecting lower elastic part 430 may be disposed on the same plane. Alternatively, when a driving signal is not applied to the coil block 120, the inner lower elastic part 410 may be disposed at a somewhat lower position than the outer lower elastic part 420.

In one embodiment of the present invention, when the concave bobbin receiving groove 330 is formed on the upper surface 320 of the base 300, using the bobbin receiving groove 330 while reducing the overall volume of the voice coil motor 600 Thus, the mover 200 may be driven in a direction away from the base 300 or the mover 200 in a direction closer to the base 300.

That is, when the mover 200 is spaced apart from the upper surface 320 of the lower base 300, the mover 200 faces the base 300 by changing the direction of the current applied to the coil block 120. The lower direction or the upper direction away from the base 300 may be driven respectively.

On the other hand, the upper elastic member 450 is coupled to the coupling boss 156 formed on the upper surface of the housing body 152 of the housing 150 of the stator 100.

The upper elastic member 450 includes an inner upper elastic portion 451, an outer upper elastic portion 452, and a connecting upper elastic portion 453.

The inner upper elastic portion 451 is coupled to the upper surface of the bobbin 210, the outer upper elastic portion 452 is disposed on the upper surface of the housing body 152. The connecting upper elastic portion 453 connects the outer and inner upper elastic portions 451 and 452.

The outer upper elastic portion 452 disposed on the upper surface of the housing body 152 is formed with a coupling hole 455 that is coupled to the coupling boss 156 formed on the upper surface of the housing body 152.

Referring back to FIG. 1, the voice coil motor 600 may further include a cover can 500.

The cover can 500 includes a top plate 510 having an opening for exposing the lens 205 of the mover 200 and a side plate 520 extending in a direction from the edge of the top plate 510 toward the base 300. It includes, the side plate 520 is coupled to the side of the base 300.

2, the bobbin 210 of the mover 200 according to an embodiment of the present invention is the upper surface 320 of the base 300 by the force generated from the coil block 120 and the magnet 250 The first direction FD and the second direction SD toward the bottom surface of the bobbin receiving groove 330 of the base 300 in a direction opposite to the first direction FD.

In an embodiment of the present invention, the bobbin 210 of the mover 200 is driven in the first direction FD when a forward current is applied to the coil block 120, and the bobbin 210 is the coil block 120. ) Is driven in the second direction SD when a reverse current opposite to the forward current is applied.

In this case, the forward current or the reverse current applied to the coil block 120 may be implemented by adjusting the voltage difference applied to both ends of the coil block 120, and the voltage difference may be implemented by, for example, a PWM circuit.

3 is a cross-sectional view conceptually illustrating the voice coil motor illustrated in FIG. 1. 4 is a graph showing a relationship between a driving current amount and a moving amount for driving the voice coil motor shown in FIG. 1.

1, 3, and 4, the mover 200 including the bobbin 210 and the magnet 250 is fixed by the lower elastic member 400 and the upper elastic member 450, and the lower and When no current is applied to the coil block 120 by the elastic force of the upper elastic members 400 and 450, the mover 200 is positioned at a position spaced apart from the bottom surface 335 of the bobbin receiving groove 330 of the base 300. It is floated.

That is, in one embodiment of the present invention, since the bobbin 210 elastically fixed to the lower and upper elastic members 400 and 450 is floated by the bobbin receiving groove 330, the bobbin 210 is a coil block 120 Can be bidirectionally driven in the second direction SD facing the top surface 320 of the base 300 or in the first direction FD away from the top surface 320 of the base 300 according to the direction of the current applied to Can be.

In order to widen the gap between the image sensor disposed below the base 300 and the lens included in the mover 200, a forward current is applied to the coil block 120, thereby causing a first magnetic field from the coil block 120. This is caused.

The first magnetic field generated from the coil block 120 works with the second magnetic field generated from the magnet 250 mounted on the bobbin 210 of the mover 200 to move the mover 200 to the upper portion of the base 300. The lifting force which raises in the 1st direction FD toward to generate | occur | produces is generated. The lifting force is increased in proportion to the strength of the forward current applied to the coil block 120.

The upper and lower elastic members 400 and 450 of the voice coil motor 600 according to the exemplary embodiment of the present invention face the mover 200 toward the base 300 when no current is applied to the coil block 120. Because of the non-pressurization, as soon as the forward current is applied to the coil block 120, the mover 200 starts to rise in the first direction FD away from the upper surface of the base 300.

Hereinafter, the current in the region where the Y-axis is positive in the graph of FIG. 4 is defined as "forward current", and the current in the region where the Y-axis is negative in the graph of FIG. 4 is defined as "reverse current".

In addition, the mover 200 of the voice coil motor 600 according to an embodiment of the present invention is the base by the bobbin receiving groove 330 of the base 300 before the forward current is applied to the coil block 120. Since it is already separated from the 300, the amount of current of about 25 [mA] is required for the mover 200 of the voice coil motor 600 according to the exemplary embodiment of the present invention to reach the point A. On the other hand, in a general voice coil motor, a current amount of about 80 [mA] is required for the mover to reach the point A, and the power consumption of the voice coil motor according to an embodiment of the present invention is about 1 / of the conventional voice coil motor. Only about three.

That is, in one embodiment of the present invention, before the current is applied to the coil block 120 using the upper and lower elastic members 400 and 450, the movable member 200 is already spaced apart from the upper surface of the base 300. Therefore, the mover 200 can be raised to a required position even with a smaller amount of current.

On the other hand, in order to drive the mover 200 of the voice coil motor 600 according to an embodiment of the present invention in the second direction SD closer to the base 300, the coil block 120 in the reverse direction instead of the forward current Apply a current.

Due to the magnetic field generated by the reverse current applied to the coil block 120 and the magnetic field generated by the magnet 250, the downward force toward the base 300 is generated in the mover 200, and The mover 200 moves in the second direction SD toward the bottom surface 335 of the bobbin accommodation groove 330 formed on the top surface 320 of the base 300.

In one embodiment of the present invention, even when the mover 200 is moved in the second direction SD, the mover 200 may be moved by a current amount that is only about 1/3 of the amount of current required by the conventional voice coil motor. .

5 is a block diagram illustrating a driving circuit for raising or lowering a mover of a voice coil motor according to an exemplary embodiment of the present invention.

1 and 5, when no current is applied to the coil block 120, the mover 200 is formed on the upper surface 320 of the base 300 by upper and lower elastic members 400 and 450. Maintains the floated state from the bobbin receiving groove 330.

On the other hand, as the current is applied to the coil block 120 to drive the floated mover 200, the mover 200 is in a first direction (FD) or the first direction toward the upper surface 320 of the base 300 It is driven in the second direction SD opposite to the direction FD.

In order to drive the mover 200 in either the first direction FD or the second direction SD, the voice coil motor 600 changes the flow of current applied to the coil block 120. The main includes a drive module 700.

The drive module 700 includes a control unit 710 and a current providing unit 790.

The control unit 710 is electrically connected with the external circuit board, and the control unit 710 generates the rising control signal S1 and the falling control signal S2.

The rising control signal S1 is a control signal for increasing the gap between the bobbin 210 of the voice coil motor 600 and the upper surface 320 of the base 300, and the falling control signal S2 is a voice coil motor ( Control signal for reducing the gap between the bobbin 210 of 600 and the top surface 320 of the base 300.

The current providing unit 790 increases the distance between the mover 200 and the upper surface 320 of the base 300 in the coil block 120 included in the stator 100 in response to the rising control signal S1. Provide a "forward current".

On the other hand, the current providing unit 790 is a "reverse current" for reducing the gap between the mover 200 and the upper surface 320 of the base 300 in the coil block 120 in response to the falling control signal S2. To provide.

The current providing unit 790 includes a power source 715, a first unit circuit unit 720, and a second unit circuit unit 730.

The first unit circuit unit 720 includes, for example, first and second switch elements Q1 and Q2. In one embodiment of the present invention, the first and second switch elements Q1 and Q2 may each include a transistor including an input terminal, an output terminal and a gate.

The output terminal of the first switch element Q1 is electrically connected to the output terminal of the second switch element Q2.

The second unit circuit unit 730 includes third and fourth switch elements Q3 and Q4. In one embodiment of the present invention, the third and fourth switch elements Q1 and Q2 may each include a transistor including an input terminal, an output terminal and a gate. The output terminal of the third switch element Q3 is electrically connected to the output terminal of the fourth switch element Q4.

In one embodiment of the present invention, the first unit circuit unit 720 and the second unit circuit unit 730 are connected in a parallel manner with respect to the power source 715. That is, the input terminals of the first and second switch elements Q1 and Q2 of the first unit circuit unit 720 and the input terminals of the third and fourth switch elements Q3 and Q4 of the second unit circuit unit 730. They are each supplied with current provided from the power source 715.

Meanwhile, the output terminals of the first and second switch elements Q1 and Q2 of the first unit circuit unit 720 and the output terminals of the third and fourth switch elements Q3 and Q4 of the second unit circuit unit 730. One end of the wire constituting the coil block 120 and the other end opposite to the one end are electrically connected to the field.

In operation, the rising control signal S1 output from the control unit 710 is applied to the gate of the first switch element Q1 and the gate of the fourth switch element Q4. The falling control signal S2 output from the control unit 710 is electrically connected to the gate of the second switch element Q2 and the gate of the third switch element Q3, respectively.

Therefore, when the rising control signal S1 is output from the control unit 710, the rising control signal is applied to the gates of the first switch element Q1 and the fourth switch element Q4, as shown in FIG. 6. (S1) is applied together. Accordingly, the first switch element Q1, the coil block 120, the fourth switch element Q4, and the power source 715 form a closed circuit, and thus, a “forward current” is applied to the coil block 120.

As the forward current is applied to the coil block 120, the distance between the mover 200 of the voice coil motor 600 and the upper surface 320 of the base 300 is increased. That is, the mover 200 is lifted from the upper surface 320 of the base 300.

On the other hand, when the falling control signal S2 is output from the control unit 710, the falling control signal to each gate of the second switch element Q2 and the third switch element Q3, as shown in FIG. (S2) is applied together. Accordingly, the third switch element Q3, the coil block 120, the second switch element Q2, and the power source 715 form a closed circuit, which causes the coil block 120 to flow in a direction opposite to the "forward current". Reverse current "is applied.

As the reverse current is applied to the coil block 120, the mover 200 of the voice coil motor 600 is moved into the bobbin accommodation groove 330 formed on the upper surface 320 of the base 300. That is, the movable member 200 descends toward the bottom surface 335 of the bobbin receiving groove 330 formed on the upper surface 320 of the base 300.

In one embodiment of the present invention, although the configuration for controlling the direction of the current flowing through the coil block 120 using four switch elements (Q1, Q2, Q3, Q4) differently, it is shown differently The direction of the current flowing through the coil block 120 may be changed using a wide variety of electrical elements.

Although in one embodiment of the present invention is shown and described in the configuration for controlling the direction of the current flowing through the coil block 120 using four switch elements (Q1, Q2, Q3, Q4) differently, The bobbin 210 may be raised or lowered by applying a voltage to both ends of the coil block 120 and adjusting a voltage difference between both ends of the coil block 120.

Hereinafter, a driving method of the voice coil motor according to an embodiment of the present invention will be described.

1 and 8, in order to drive the voice coil motor 600, for example, a reverse current FC (or an initial driving current) is applied to the coil block 120 to refer to the bobbin 210. Move to position

In one embodiment of the present invention, the reference position may be the bottom surface 335 of the bobbin receiving groove 330 formed on the upper surface 320 of the base 300.

At this time, in order to contact the bobbin 120 to the bottom surface 335 of the bobbin receiving groove 330 formed on the upper surface 320 of the base 300, the reverse current FC of the specific current amount D to the coil block 120. When the bobbin 210 is applied, the bobbin 210 descends to the bottom surface 335 of the base 300 so that the base 300 and the bobbin 210 collide with each other, and thus the waiting time until the bobbin 120 is stabilized. Required.

In one embodiment of the present invention, the moving speed of the bobbin 210 due to the reverse current FC (or the initial driving current) of the specific current amount D applied to the coil block 120 decreases as the reference position is closer to the reference position. In order to reduce the waiting time for the bobbin 210 in contact with the position to stabilize, the reverse current FC having a specific current amount D first in the coil block 120 as shown by the advantaged dashed line of FIG. 8. After applying), the specific current amount D of the reverse current FC is gradually decreased for a predetermined time until the bobbin 210 is in contact with the bottom surface 335, thereby decreasing the falling speed of the bobbin 120. Reduce the waiting time of 120.

Subsequently, the amount of current of the reverse current FC applied to the coil block 120 is decreased to separate the bobbin 210 from the reference position again, and when the bobbin 210 reaches the initial position S, the coil block 120 Apply a forward current (SC) to the. The forward current SC can be increased continuously or stepwise.

Subsequently, when the optimum focus required between the lens 205 fixed to the bobbin 210 and the image sensor module is formed, the current amount of the forward current FC is kept constant so that the bobbin 210 corresponds to the optimum focus. Stop at the position

The step of stopping the bobbin 210 at a position corresponding to the optimum focus further includes moving the bobbin 210 to a position slightly outside the position of the optimum focus and reducing the amount of forward current in the coil block 120. As a result, the bobbin 210 may be returned to the position of the optimum focus, and the fine focusing process may be performed to finely adjust the focus between the lens 205 of the bobbin 210 and the image sensor module.

Subsequently, an optimal focus is formed between the image sensor module and the lens 205, and the image sensor module generates an image or a video of the subject with the optimal focus.

Meanwhile, referring to FIGS. 1 and 9, the bobbin 210 is moved to a reference position by applying a forward current SC of a specific current amount D to the coil block 120 of the voice coil motor 600.

In one embodiment of the present invention, the reference position may be an inner surface of the top plate 510 of the cover can 500.

Subsequently, the amount of current of the forward current SC in the coil block 120 is decreased to separate the bobbin 210 from the upper plate 510 of the cover can 500, which is the reference position, and the bobbin 210 is located at the initial position S. ), The reverse current (FC) is applied. The reverse current (FC) can be increased continuously or stepwise.

Subsequently, when the required focus is established between the lens 205 fixed to the bobbin 210 and the image sensor module, the current amount of the reverse current FC is kept constant so that the bobbin 210 corresponds to the optimum focus. Stop at the position

The process of stopping the bobbin 210 at a position corresponding to the optimum focus may include moving the bobbin 210 to a position slightly out of the position of the optimal focus, and of the reverse current SC in the coil block 120. By slightly increasing the amount of current, the bobbin 210 may be returned to the optimal focus position, and the fine focusing process may be performed to more precisely adjust the focus between the lens 230 of the bobbin 210 and the image sensor module. .

Subsequently, an optimal focus is formed between the image sensor module and the lens 205, and the image sensor module generates an image of the subject with the optimal focus.

In the method of driving the voice coil motor according to an exemplary embodiment of the present invention, the bobbin 210 illustrated in FIG. 1 may be any one of an upper surface 320 of the base 300 or an inner surface of the upper plate 510 of the cover can 500. Set the reference position by touching one, and apply a current to the coil block 120 from the reference position until the position that achieves the optimal focus with the image sensor module to focus the focus between the mover 200 and the image sensor module. Although the method of adjusting is illustrated and described, alternatively, the first current is applied to the coil block 120 to move the bobbin 210 to the reference position, and the optimum between the lens 205 and the image sensor module with respect to the subject. Data for maintaining focus may be calculated, and the bobbin 210 may be moved from the reference position based on the data by applying an amount of current corresponding to the data to the coil block 120. .

In this case, the current amount of the current applied to the coil block 120 has an intensity corresponding to the data, and the reference position is the inner surface of the upper plate 510 of the cover can 500 or the upper surface 320 of the base 300. Can be.

As described above in detail, the lens-mounted bobbin is floated from the bobbin accommodation groove formed on the upper surface of the base on which the image sensor is mounted, and a forward current or a reverse current is applied to the coil block to move the mover including the bobbin from the base. By driving in both directions in the direction away or approaching the base, the voice coil motor can be driven with low current, reducing power consumption, adjusting the focus between the lens and image sensor in a shorter time, and reducing the contact noise caused by the bobbin driving. It has an effect that can be reduced.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the true scope of the present invention should be determined by the following claims.

600 ... Voice Coil Motor 100 ... Stator
200 ... operator 300 ... base
400 ... lower elastic member 450 ... upper elastic member
500 ... Cover can

Claims (22)

A stator including a coil block and a housing for fixing the coil block;
A mover including a bobbin disposed inside the coil block and having a lens fixed therein, and a magnet disposed on the bobbin facing the coil block;
A base in which the housing is fixed and an opening is formed at a position corresponding to the lens, and a bobbin receiving groove is formed on an upper surface facing the bobbin to receive a lower surface of the bobbin; And
When no driving signal is applied to the coil block, a lower elastic member fixed to the bobbin and the base such that a gap is formed between the bottom surface of the bobbin and the bottom surface formed by the bobbin receiving groove regardless of the posture of the mover. Voice coil motor comprising a. The method of claim 1,
And the housing includes a plate-shaped housing body having an opening exposing the bobbin and a plurality of pillars protruding from the lower surface of the housing body toward the base. The method of claim 2,
A plurality of coupling bosses protrude from an upper surface of the housing body, and an upper elastic member coupled to the upper surface of the bobbin is coupled to the coupling bosses. The method of claim 1,
The bobbin is formed in a cylindrical shape and the magnet is a voice coil motor formed in a plate shape facing the coil block. The method of claim 1,
And a plane area of the bobbin receiving groove of the base is larger than that of the bobbin. The method of claim 1,
The lower elastic member includes an inner lower elastic part coupled to a lower surface of the bobbin, an outer lower elastic part disposed on an upper surface of the base, and a connecting lower elastic part connecting the inner and outer lower elastic parts. The method according to claim 6,
The inner lower elastic part is formed in an annular ring shape, the inner lower elastic part is a voice coil motor formed in a size accommodated in the bobbin receiving groove. The method according to claim 6,
And a driving coil is not applied to the coil block, wherein the inner lower elastic part, the outer lower elastic part, and the connecting lower elastic part are disposed on the same plane. The method of claim 1,
Voice coil motor having a shock absorbing member is disposed on the bottom surface formed by the bobbin receiving groove. 10. The method of claim 9,
The shock absorbing member is a voice coil motor comprising any one of a sponge, elastic resin and rubber. The method of claim 1,
And a cover can surrounding the stator and exposing the lens. A stator including a coil block and a housing for fixing the coil block;
A mover including a bobbin disposed inside the coil block and having a lens fixed therein, and a magnet disposed on the bobbin facing the coil block;
A base in which the housing is fixed and an opening is formed at a position corresponding to the lens, and a bobbin receiving groove is formed on an upper surface facing the bobbin to receive a lower surface of the bobbin; And
A lower elastic member fixed to the bobbin and the base such that a gap is formed between a bottom surface of the bobbin and a bottom surface formed by the bobbin receiving groove;
The bobbin supported by the lower elastic member is any one of a first direction away from the base by a first force generated by the coil block and the magnet and a second direction approaching the base by the bobbin receiving groove. Voice coil motor driven in one direction. The method of claim 12,
Forward current is applied to the coil block when the bobbin is driven in the first direction, and reverse current flowing in the opposite direction to the flow of the forward current is applied to the coil block when the bobbin is driven in the second direction. Voice coil motor. The method of claim 12,
A voice coil motor for controlling the voltage difference between both ends of the coil block to drive the bobbin in any one of the first direction and the second direction. 15. The voice coil motor of claim 14 wherein the voltage difference is generated and controlled by a PWM circuit. A stator including a coil block and a housing for fixing the coil block;
A mover including a bobbin disposed inside the coil block and having a lens fixed therein, and a magnet disposed on the bobbin facing the coil block;
A base in which the housing is fixed and an opening is formed at a position corresponding to the lens, and a bobbin receiving groove is formed on an upper surface facing the bobbin to receive a lower surface of the bobbin;
A lower elastic member fixed to the bobbin and the base such that a gap is formed between a bottom surface of the bobbin and a bottom surface formed by the bobbin receiving groove; And
A forward current in response to a control unit for generating a lift control signal for raising the bobbin from the base and a drop control signal for lowering the bobbin into the bobbin receiving groove, and the rise and fall control signals of the control unit, respectively. And a drive module including a current providing unit for providing one of reverse currents to the coil block. 17. The method of claim 16,
The current providing unit includes a first unit circuit part in which first and second switch elements are connected in series, and a second unit circuit part in which third and fourth switch elements are connected in series,
The first and second unit circuit parts are electrically connected in a parallel manner with respect to power, a first end of the coil block is connected between the first and second switch elements, and the third and second And a second end of the coil block connected between the four switch elements. 18. The method of claim 17,
The rising control signal is provided to the first and fourth switch elements so that the forward current is applied to the coil block, and the falling control signal is provided to the second and third switch elements so that the coil block is Voice coil motor to which reverse current is applied. A base having a bobbin receiving groove formed thereon, a stator including a magnet disposed on the base and disposed above the bobbin receiving groove and including a magnet, a coil block fixed to the base and facing the magnet, and the bobbin. In the voice coil motor comprising an elastic member to float on the upper receiving groove,
Applying an initial driving signal to the coil block to move the bobbin to a reference position to align the bobbin;
Moving the bobbin from the reference position to a focus position by applying a driving current of increasing or decreasing level to the coil block; And
And maintaining the level of the drive current constant when the optimum focus is formed between the lens and the image sensor module to stop the bobbin at a position corresponding to the optimum focus. 20. The method of claim 19,
The reference position is a voice coil motor driving method of any one of the bottom surface formed by the bobbin receiving groove and the inner surface of the cover can covering the bobbin. 20. The method of claim 19,
The step of stopping the bobbin at a position corresponding to the optimal focus may include moving the bobbin to a position away from the position of the optimal focus; And
And applying the current for position correction to the coil block again to return the bobbin to the position of the optimal focus. 20. The method of claim 19,
In the step of aligning the bobbin by applying the initial drive current to the coil block to move the bobbin to a reference position,
And a moving speed of the bobbin due to the initial driving current decreases closer to the reference position, thereby reducing the time required for the bobbin to collide with the reference position to stabilize the bobbin.

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